Posterior fixation as is commonly used to help stabilize the treated spine constructs for various degenerative and traumatic spine conditions and can also be an adjunct to interbody fusion.
Posterior fixation often includes the use of a pedicle screw and rod system, where the pedicle screw is anchored into a vertebra pedicle and vertebral body. A rod is then attached between heads of at least two adjacent pedicle screws that are located ipsilaterally on the pedicle or vertebral body. This configuration helps to immobilize the treated spine construct and aid in the interbody fusion. In instances where the bone quality is poor the pedicle screw can loosen after surgery, requiring a revision surgery to replace or re-stabilize the loosened screw.
To address the anchoring problems of pedicle screws in poor quality bone, surgeons have been placing bone cement (PMMA) into the vertebral body and pedicle, then placing the pedicle screw within the bone cement. Once cured, the cement acts as a foundation for the pedicle screw allowing it to be securely anchored within the vertebral body and pedicle.
There remains a need for methods and instruments that can safely access the pedicle and deliver bone cement via a minimally invasive surgery (MIS) that can also work in conjunction with the various MIS techniques and instruments used for pedicle screw and rod fixation.